1. Field of the Invention
The invention is in the field of electrical load control circuits.
2. Description of the Prior Art
In the past, various schemes have been employed for gating triacs for AC load control. For example, a small resistance and a switch have been connected between the first anode of the triac and its gate. The switch may be a reed relay or light-sensitive switch. When an appropriate control signal is applied to the switch, the switch closes and current coupled through the resistance from the first anode is supplied to the gate, turning on the triac. With this type of circuit, when the triac is nonconductive, the gate is left open and high leakage currents or irregularities of line voltage can trigger the triac spontaneously.
It has not been appreciated, so far as the inventor is aware, in the prior art to utilize a continuous transformer gate-actuation circuit for a triac in a load control wherein the appropriate polarity of transformer secondary connection to the triac gate has been observed.